Cardiac probes are used for cardiac stimulation and to pick up electrical signals originating from the heart. A probe comprises two tips: one called proximal, which is, in the context of cardiac stimulation, intended to be connected to the signal generator; the other is called distal and is intended to be placed in contact with the cardiac muscle, e.g., the inner surface of the cardiac muscle.
The probe comprises an electrical conductor comprising a metal wire coiled in a spiral or helical manner and arranged inside a biocompatible flexible sheath made, for example, of silicone rubber. The conductor is connected to an electrode, e.g., a ring-shaped or cylindrical electrode, arranged at the distal tip of the probe.
Various incidents can occur on the occasion of use of cardiac probes. On the one hand, it is necessary to replace a probe which is not functioning correctly with a new probe. On the other hand, focuses of infection may break out at the tip or along the probe.
Extraction of the probe is imperative in the preceding cases. For this purpose, a known extraction procedure calls for pulling on the probe by applying a constant traction on the order of 1N to 5N until there is detachment of the probe from the surface of the cardiac muscle. This operation, which is long and arduous for the patient, often takes several days.
Documents DE 3,937,594, U.S. Pat. Nos. 4,574,800 and 4,988,347 describe three different devices for extraction of a cardiac probe, the common element of which is the following. These devices, expansible through enlargement of their outside diameter, are inserted inside the electrical conductor coiled in a spiral up to the vicinity of the distal tip of the probe. Then they are fastened to this distal tip by means of expansion of their outside diameter, so as to be able to exercise a traction on this distal tip. One drawback resulting from the use of these known devices is the risk of tearing of the fibrin surrounding the distal tip of the probe and, possibly, of a portion of the myocardium.